The invention relates to an open, secure electronic signature system including a business application (10), said business application comprising a programming interface (42) configured to make a request to sign a document (20) to a signature manager (40) for a user (30), the system being characterised in that said business application (10) is capable of defining content to be signed, identifying criteria and selecting a signatory user (30), defining the use of a type of digital ID, collecting signature properties and demanding a signature format. The signature manager (40) is capable of coordinating said signature request by performing the following steps: verifying the identity and the authorisation of the business application (10); verifying the identity of the signatory user (30); recovering the document (20) to be signed; preparing the signature request using the calculations of fingerprints of the data to be signed; and sending a notification of the signature request to signature services (60) of the user (30). The user (30), by means of said signature services (60), is capable of monitoring the execution of the signature process by activating the private key corresponding to a certificate (61) of the user (30) complying with the selection criteria sent to said signature manager (40) by the business application (10) with a view to encrypting the fingerprint of the data to be signed. The invention also relates to the method for producing and processing a signature request implemented in the above system.